Thomas a



(No Model.)

T. A. EDISON. ELEOTRIO SIGNALING APPARATUS.

No. 488,304. Pat gnted Oct. 14,1890.

Units TATES THOMAS A. EDISON, OF MENLO PARK, NET/V JERSEY.

ELECTRIC SIGNALING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 438,304, dated October14, 1890.

Application filed December 15, 1884. Serial No. 150,343. (No model.)

To all whom it may concern/.-

Be it known that I, THOMAS A. EDIsON, of Menlo Park, in the county ofMiddlesex and State of New Jersey, have invented a new and usefulImprovement in Electric Signaling Apparatus, (Case No. 634,) of whichthe following is a specification.

My invention relates to that class of individual call or signalingsystems in which the signal-receiving instruments consist each of anelectr c-magnet located in the line in front of which is placed avibrating pendulum or reed, all such pendulums or reeds having differentrates of vibration and each being adapted when in motion to produce asignal, preferably by striking upon a bell-gong. Thetransmitting-instrument at the main or central oflice is a magnet with apendulum-armature having an adjustable bob or Weight upon it, so thatits swing may be altered to correspond with that of such of thereceiving-pendulums as it may be desired to effect. Thetransmitting-pend ulum makes and breaks the line-circuit as it swings,and thus throws the line-current into pulsations or vibrations, whichaffect the signaling-magnets so that that pendulum whose rate ofvibration is the same as that to which the transmitting-pendulum hasbeen adjusted will be caused to afiect its bell or local circuit, andthe desired signal will be produced at this point, while all the otherswill remain unaffected.

The object of my invention is to provide simple and effective meanswhereby in a system such as that just described a person at any one ofthe receiving-points may signal the transmitting-station without causingany effect in the other signal-receivers.

The accompanying drawing is a diagram of a system embodying myinvention.

A and B are the signal-receivers arranged in series in the line L. Eachis composed of a magnet to in the line and a reed or pendulum I), havingweight 0 and suspended in front of I the magnet the proper distance awaynot to be affected, except by current-pulsations corresponding with orin unison or accord with its rate of vibration. The reeds or pendulumsare of different lengths and the Weights of different sizes, as shown,so that their rate of vibration will be different, for the purposealready explained. Bells d e are mounted opposite each other at thelimit of swing of the reed or pendulum, so as to be struck by the ball 0when the pendulum acquires a definite swing. At the central point fromwhich the line runs is located the signal-transmitter C, composed of areed or pendulum 2', having an adjustable weight k and graduated to showthe adjustment, and a magnet Z opposite the reed or pendulum. The reedor pendulum 2' makes and breaks the circuit of line-battery D at thespring m. The line is connected to switch E, and the signal-transmitteris arranged in a loop between the battery D and one point of the switch,a bell F being located in a loop between D and the other point of theswitch, whose function will be presently explained.

The means which I provide for signaling the central or transmittingstation from a receiving-point consists of a device whereby irregularpulsations may be given to the linecurrent. Such pulsations are employedto actuate the bell F at the central station, but can have no effect onany of the receivingpendulums, since these are affected only by regularvibrations. When the transmitter is not in use, the switch E is placed,as shown, so that such transmitter is cut out and the bell F is incircuit in readiness for a call, and such switch is shifted to its otherposition when the transmitter is operated.

I have shown two different devices at the receiving stations. At stationA is placed a simple key G in the line which is operated by hand toproduce the desired irregular-current pulsations; but this arrangement Ido not claim herein.

In the present invention I employ a circuitcontroller which by a singlemovement causes several makes and breaks in the circuit, said makes andbreaks being of different number and rate from that required to operatethe vibrating receivers.

I prefer the device shown in connection with station E. This consists ofa break-Wheel H, provided with a handle for turning it and provided withteeth 0, situated at irregular intervals upon its periphery. Theline-conductors are connected with springs g h, which are normally incontact, and spring h has a tooth resting normally in the depressions ofwheel H. When such wheel is turned, teeth 0 serve to break the contactbetween 9 and h at irregular intervals, and the bell F is rung by thevibration of currents thus caused. Any other suitable form ofbreak-wheel or other circuit-breaker adapted to make and break thecircuit at irregular intervals may evidently be employed.

What I claim is- 1. The combination, in an individual signaling system,of a line including a source of electricity, a transmitter, and severalvibrating receivers, the rates of vibration of which are different eachfrom the other, and a circuit controller at each receiving-stationhaving several making and breaking devices, of a number so arranged asto be insufficient to operate any of the vibrating receivers, whereby bya single movement of the controller a plurality of impulses may be sentover the line to operate the central-oflicc sig- THOS. A. EDISON.

Witnesses:

WM. H. MEADoWcRoEr, THOS. G. GREENE, Jr.

